U.S. Pat. No. 5,652,021 describes a flame-based deposition technique termed combustion chemical vapor deposition or “CCVD”. U.S. Pat. No. 5,997,956 describes a CCVD process using near-supercritical fluid solutions. The teachings of each of the above-mentioned U.S. Patents are incorporated herein by reference. The techniques taught in these patents allow for large-scale, open-atmosphere deposition of films or coatings of a variety of materials, including metals, polymers, metal oxides, metalloid oxides, and mixed oxides, as thin layers on various substrates and also provide for production of powders of fine, generally uniform size. In these processes, atomization of chemical precursor solutions may be effected by passing the precursor solutions under pressure through narrow diameter needles or nozzles.
While CCVD is an effective means of depositing very thin films, and while thicker films may be deposited by increasing deposition times and/or increasing the number of passes of a CCVD flame over a substrate, there may be practical constraints that limit the usefulness of depositing thicker films or coatings, e.g., 10 microns or greater, by conventional CCVD. Accordingly, it is a primary object of the present invention to produce relatively thick coatings, e.g., 10 microns thick or above, preferably 20 microns thick or above. However, the invention is not limited to these thicknesses, and the invention is generally useful for depositing coherent materials, such as films or coatings, as thin as about 0.1 micron and up to about 1000 microns or above.